The progress of the dental technique and the medical treatment of these last years has carried to excellent solutions for nearly the totality of dental pathologies regarding hard tissues such as tooth and bone, but not for periodontal tissue and gum, that also carry out an extremely important role in the conservation and good functionality of the masticator apparatus.
The periodontal tissue and the gum in particular assures to the system tooth-periodontal tissue-bone an essential protection from all those pathogenic and destabilizing agents that come from the oral cavity.
Moreover chronic infections in the oral cavity are absolute insensitive to systemic treatment by means of antibiotic. One of the scopes of present the invention is to supply adequate means for the protection of the masticator apparatus and drug delivery in the oral cavity, using material adapted for this purpose.
Rifaximin is known like a powerful and effective antibiotic to wide number of pathogenic agents. Its use is currently relegated to the treatment of the diarrheas and internal infections. One characteristic that renders precious such an antibiotic is that it does not permeate through the mucosae. This fact allows a local use of such an antibiotic at high concentrations, with a great efficacy, a null systemic concentration and therefore collateral effects. On the other hand, the rifaximin possesses a very low solubility in the physiological liquids. For this reasons it remains in form of small crystal, of intense red color, dispersed in the place of administration. For aesthetic reasons, this fact prevents its use in all those places, like the mouth, where the patient wishes to maintain a socially acceptable aspect. Moreover, the drug in the form of small crystals, generates a peaky of concentration, at the moment of the application but then it disperses itself quickly far away from the point where it is placed losing its effectiveness. In truth, a continuous and calibrated delivery along the time of rifaximin would be a very good tool for the treatment of a wide ensemble of gram-positive and gram-negative bacteria and it renders possible its use outside of the intestine.
An important class of materials is that one of the, so-called, bi-phasic materials. They are constituted from two phases: a solid one, made by an elastic matrix that maintains its own shape and is able to confer to the material a strong rubber-like elasticity, and a liquid part that fills up its pores that, in gels, are constituted by the molecular interstices. Their importance is given by the fact that the overwhelming majority of biological tissues, for instance, the cartilage, the derma, the endothelia, the tendons, the gray matter of the brain, the chromosomes and the several organelles of the cell are made up of bi-phasic materials. They can have a strong elasticity and can be resistant to repeated cycles of loading like tendons. The volume and the shape that a bi-phasic materials assume derive from the equilibrium of many forces; in exemplified way, it can be said that the fluid enters in the pores, or in the inter-molecular spaces of the solid matrix (polymer network), and swells it for an effect of “suction”. This phenomenon is generated from the affinity (attractive force) existing between the molecules of the fluid and those of the solid matrix. The solid matrix (polymer networks) opposes itself to this swelling tendency till an equilibrium volume is reached.
Varying the affinity between the polymer network, constituting the solid matrix, and the fluid, the water content inside of a biphasic material can be regulated. Usually the ratio in weight between fluid (water) and solid part (polymer net) can arrive to advanced values also to 10. The present invention consists in having designed a new method and way of administration of the rifaximin dosed and continued in the time, by means of the formulation and realization of suited bi-phasic materials and devices that allow it.
By means of the devices, matter of this patent, the use of the rifaximin becomes possible outside the intestine (e.g., in the oral and pharyngeal or nasal cavity, in the rectum and vagina). In particular they allows high level, constant in time, of concentration of rifaximin in aqueous body fluids avoiding the intense red color that it produces in the neighboring of the place of administration.